Redis Data Structure

ZMON stores its primary working data in Redis. This page describes the used Redis keys and data structures.

Queues are Redis keys like zmon:queue:<NAME> of type “list”, e.g. zmon:queue:default.

New queue items are added by the ZMON Scheduler via the Redis “rpush” command.

Important Redis key patterns are:

zmon:queue:<QUEUE-NAME>

List of worker tasks for given queue.

zmon:checks

Set of all executed check IDs.

zmon:checks:<CHECK-ID>

Set of entity IDs having check results.

zmon:checks:<CHECK-ID>:<ENTITY-ID>

List of last N check results. The first list item contains the most recent check result. Each check result is a JSON object with the keys ts (result timestamp), td (check duration), value (actual result value) and worker (ID of worker having produced the check result).

zmon:alerts

Set of all active alert IDs.

zmon:alerts:<ALERT-ID>

Set of entity IDs in alert state.

zmon:alerts:<ALERT-ID>:entities

Hash of entity IDs to alert captures. This hash contains all entity IDs matched by the alert, i.e. not only entities in alert state.

zmon:alerts:<ALERT-ID>:<ENTITY-ID>

Alert detail JSON containing alert start time, captures, worker, etc.

zmon:downtimes

Set of all alert IDs having downtimes.

zmon:downtimes:<ALERT-ID>

Set of all entity IDs having a downtime for this alert.

zmon:downtimes:<ALERT-ID>:<ENTITY-ID>

Hash of downtimes for this entity/alert. Each hash value is a JSON object with keys start_time, end_time and comment.

zmon:active_downtimes

Set of currently active downtimes. Each set item has the form <ALERT-ID>:<ENTITY-ID>:<DOWNTIME-ID>.

zmon:metrics

Set of worker and scheduler IDs with metrics.

zmon:metrics:<WORKER-OR-SCHEDULER-ID>:ts

Timestamp of last worker or scheduler metrics update.

zmon:metrics:<WORKER-OR-SCHEDULER-ID>:check.count

Increasing counter of executed (or scheduled) checks.